.box .sbox{
    width: 100%;
    height: 300px;
    background-color: red;
    margin-bottom: 10px;
}
a {
    display: block;
    position: fixed;
    bottom: 50px;
    right: 10px;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    background-color: antiquewhite;
   font-size: 5px;
   text-align: center;
   line-height: 50px;
   color: #000;
   text-decoration: none;
}
html{
    scroll-behavior: smooth;
}